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Cited by 198Neuroscience and Neural EngineeringTactile and Sensory InteractionsVisual perception and processing mechanisms

Simulation of a phosphene-based visual field: Visual acuity in a pixelized vision system

Cha, Kichul, Horch, Kenneth, Normann, Richard A.·1992·Annals of Biomedical Engineering
DOI 10.1007/bf02368135
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Abstract

A visual prosthesis for the blind using electrical stimulation of the visual cortex will require the development of an array of electrodes. Passage of current through these electrodes is expected to create a visual image made up of a matrix of discrete phosphenes. The quality of the visual sense thus provided will be a function of many parameters, particularly the number of electrodes and their spacing. We are conducting a series of psychophysical experiments with a portable "phosphene" simulator to obtain estimates of suitable values for electrode number and spacing. The simulator consists of a small video camera and monitor worn by a normally sighted human subject. To simulate a discrete phosphene field, the monitor is masked by an opaque perforated film. The visual angle subtended by images from the masked monitor is 1.7 degrees or less, depending on the mask, and falls within the fovea of the subject. In the study presented here, we measured visual acuity as a function of the number of pixels and their spacing in the mask. Visual acuity was inversely proportional to pixel density, and trained subjects could achieve about 20/26 visual acuity with a 1024 pixel image. We conclude that 625 electrodes implanted in a 1 cm by 1 cm area near the foveal representation of the visual cortex should produce a phosphene image with a visual acuity of approximately 20/30. Such an acuity could provide useful restoration of functional vision for the profoundly blind.

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31 of 31 references verified0 citation errors · 0 not checkable

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  • Research using simulated prosthetic vision suggests that obtaining a wide field of view (FOV) is important for both mobility and object recognition tasks.

    “Research using simulated prosthetic vision suggests that obtaining a wide field of view (FOV) is important for both mobility and object recognition tasks.61–64”

    From Visual Prostheses in the Era of Artificial Intelligence Technology (2025) · cites this paper as [63]

  • Cha et al. and Dagnelie et al. have shown that approximately 700 electrodes could provide a blind volunteer with useful visually guided mobility.

    “For example, Cha et al. (44) and Dagnelie et al. (45) have shown that approximately 700 electrodes could provide a blind volunteer with useful visually guided mobility.”

    From Visual percepts evoked with an intracortical 96-channel microelectrode array inserted in human occipital cortex (2021) · cites this paper as [44]

  • In a series of psychophysical experiments, it has been estimated that 625 electrodes implanted at the primary visual cortex could be enough for reading (although to lower speeds) and to navigate through complex visual environments.

    “In a series of psychophysical experiments, it has been estimated that 625 electrodes implanted at the primary visual cortex could be enough for reading (although to lower speeds) and to navigate through complex visual environments (Cha et al., 1992).”

    From Toward Long-Term Communication With the Brain in the Blind by Intracortical Stimulation: Challenges and Future Prospects (2020) · cites this paper as Cha et al., 1992

  • The functional vision that could be restored with an array of intracortical microelectrodes implanted into the brain is in part related to the number of implanted electrodes, the interelectrode spacing, and the specific location of each microelectrode in the brain.

    “The functional vision that could be restored with an array of intracortical microelectrodes implanted into the brain is a function of many parameters, but it is in part related to the number of implanted electrodes, the interelectrode spacing, and the specific location of each microelectrode in the brain (Cha et al., 1992; Dagnelie et al., 2006).”

    From Toward Long-Term Communication With the Brain in the Blind by Intracortical Stimulation: Challenges and Future Prospects (2020) · cites this paper as Cha et al., 1992

  • Results of several simulation studies suggest that the amount of visual input required to perform basic visually guided tasks is not as great as one might expect.

    “Fortunately, despite the above-mentioned figures, the results of several simulation studies suggest that the amount of visual input required to perform basic visually guided tasks is not as great as one might expect.”

    From Toward Long-Term Communication With the Brain in the Blind by Intracortical Stimulation: Challenges and Future Prospects (2020) · cites this paper as Cha et al., 1992

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Authors
Cha, K., Horch, K., & Normann, R. A.
Affiliations
University of Utah (US)
Venue
Annals of Biomedical Engineering
Publisher
Springer Science and Business Media LLC
Published
1992-07
Volume
20
Issue
4
Pages
439-449
ISSN
  • 0090-6964 (ISSN-L)
  • 1573-9686
DOI
10.1007/bf02368135
OpenAlex
W1965889802
Cited by
198
References
31
Citations by year
2026: 1 · 2025: 2 · 2024: 4 · 2023: 3 · 2022: 8 · 2021: 5 · 2020: 5 · 2019: 5 · 2018: 4 · 2017: 5 · 2016: 6 · 2015: 6 · 2014: 11 · 2013: 9 · 2012: 8
FWCI
0.68
Type
journal article
Language
en
Open access
closed
Licence
www.springer.com/tdm (tdm)
Locations
  • Annals of Biomedical Engineering (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuroscience and Neural Engineering
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Tactile and Sensory Interactions
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Visual perception and processing mechanisms
Keywords
visual prosthesis, phosphenes, visual acuity, electrode arrays, electrode spacing, pixel density, fovea, psychophysics
MeSH terms
Blindness, Electric Stimulation, Electrodes, Implanted, Humans, Models, Biological, Phosphenes, Prosthesis Design, Sensory Aids, Visual Acuity, Visual Cortex, Prostheses and Implants

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